SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '038d752fb8b3757d2e7f8416c2b90b0ddcbc6e12ef6577f05588ae971419d949' 
  AND token = 'yMXGVhLn6dNWH5Z+qdfGBYYBazmAhmF7/qd7EwOyp9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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