SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c86c0d79c5cca6d770f6b52ac14749121fe41767145faa45ef37f58789b0b48' 
  AND token = 'nXlw6YzbOdZ1uJFlW3tD8e6tAwUxVviWDUr+RohvTfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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