SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18d770ab3c7982ad20f393724f2a2b67f48071ed4705a8118941b05c8837dbaf' 
  AND token = 'K+vlquYZ9pVd4br25h2Y1VB4sidaOeUDKEjge+oJV50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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