SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e70855baadd635efd10c611012286014d81df7a09ad8d62bd6f09ca0f49830bb' 
  AND token = 'hj4PfOjcTAmdmOj9DGHOVg3nWEghnPbp+/kYSHlmb1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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