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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4462e1bad88db29f7fef41a30ef5707aca96df0f2e50bf59221ff9711a440b6f' 
  AND token = '+JfX7oxHgmOStTxkO+yZQsspkMauNh3Ug/U++mTEdPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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