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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a71b0b2147d63358f3a748e771eb9792c1ddf0c6d5d5e47c4565ea7217b6b9ca' 
  AND token = 'wBbcu9Mt2TcHylT0xFEmFPtc8APnEyWbrQIyonc721Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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