SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '004d2f178b2f5c72d9ff050c989481e712feaf98a1d115d723a0910499e06c35' 
  AND token = 'g/cPYJt3aao7sU3PHL//RnXhCnWtrnqFZ9qsIsbEaxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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