SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b9189351ef377952628070aac3501492b4bb960f54b130a4294a067bfb7e130' 
  AND token = 'F+UzP4Q0XSsyPINaxsfuOzPOqy50eCQ6hMrBHuM4yP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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