SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de107ddaf8b1ca15464bf3c670fe5a7fb5aa5d7a229bd63f685593cf31196516' 
  AND token = 'mm0KAUMqM/BQQiHI2Fw8hAGzDpLkjKRLK5NA6aJWIm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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