SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1858753fdcc25999237c7391348f86ef45250d272c51cc47bb6defb32f17a74d' 
  AND token = '5NVj51ARQknRlJJXRLMIWKZSK6EF5/v98ghl1RM0mXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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