SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d77271dd24f5720c94b85e7ee8f2495e1eaeb612c43eb46d2fee352ece05be9' 
  AND token = 'J0G5PfJreUKo0KK9CvY0Nvem3ZMQ6BN0Wwl6cgoBv8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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