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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1996c416f08a3bc1d4839aff0c57ceb1722e45885618b87595b0adc0bc9da994' 
  AND token = '8DVhklS5D+kSBizc0Z1Ki2+eXZU1/DiBpYrUmXAgcmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}