SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c161cebd2a0192507eaa78acb0a88e9427abfa93c457d78fe7a7151a5a26a3b4' 
  AND token = '5cear63nE+GXTOnHVgbMRQbNbQuDxnphuPkARsgN+Fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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