SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2358a9d42469f407066f4c0c8b37d4fa546427488b03538f2b8b8832deadde8' 
  AND token = 'cPmAOJc0JI7yzvRWgrKyPGI9IyNnpZZcd5ms+XRhdoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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