SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f596d26f4119c9dcf63ebc2d8805c295e6d55aed6e99d4dbb6f23b50be864b3b' 
  AND token = 'ZaHhXg3n4b2xj91LLVWk+j+hibrCQsgQ6ar4tQI3b1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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