SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a10e5dc48d4940c6421dcf72b41ba9922d438b318a06d797fc1301c679bfd57' 
  AND token = 'Sr6YBr9dSRloGv5BDHJMD9QjLXKOXIJ+OtWOcBWAgSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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