SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39fa1b759ad3378b068693c7eb31824d945e3772b562093f80b8b3b0205f74aa' 
  AND token = 'Y8MS3MapIHLSaoLfmO01sqvxOCXEcYGZZF5FWEEVM30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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