SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f614fe451e2a95be3f7577fabf9bbeddcdd4b0e604f6fb6c697f28cc08c5ee27' 
  AND token = 'Ad++YskUhJpq8hGaved+IKhy98sBm1jubQ8S8FEfrrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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