SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '793a6d43dd98c9799e7bef4195639eaecd66763980e38e9a81b435ebee0ef19d' 
  AND token = 'Qwju3TxBxnRDdfdI16QcSfyF5GAYLUv/caLB6Lx0Va8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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