SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d2a2540da6e9ea3398fdf2e30dfdc663fccd90c72a539bdb3d2097b42c8bb76' 
  AND token = 'WBRUzvRzzKc5adyrIwjTMQBlo3iNqEDhXaNI3wMWXRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}