SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18d00dc65a4bb204c7458edc9c1bd53d77d25636f9a01bd226b2a18b0efe67d1' 
  AND token = '1eSQCM6qhtzhCJV8IOR+ELBIWOg/o7pwvFXJmvvd2TQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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