SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66fe005a53a33c234dd5061278fc429b77e13a30d0ae80038ea21e71dd639836' 
  AND token = 'DZ6Ga0UOvjFqX/gJ0vv5Tv+rVJQRJfh+3HmSRYEIfQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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