SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '944445edeff753fa2426e3fb38546521b7ca49518fd70f48419a21359da310a7' 
  AND token = 'P3pEHvq+Kj9hpqTB0DkmyJIF2KJQ//vizOtpcdaUfL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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