SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e88badb4e4a9e48e19b22f1955e6085fde27079cba4127d724153de6aa28592' 
  AND token = '4yfje8VjGNYPB/YHF6In6LaxnyGwKmlEdRizpv3/uBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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