SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4aeee8c4a620705fb86aebffd9179a54d8aa0cd264b56d189f8f335f7f7f5468' 
  AND token = '6NCxIxf+FBLLQb4QJ8CXdug57XRXE69k2AKL3wAcs/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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