SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2ff555cc22e97a70323e91680e6be765374db469935c98fdc8b5c785e7d42e9' 
  AND token = 'OQG67NiaaSZXgbVU3MVroArulsVSXjzF1LR/2JfUj4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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