SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd940cb54d60ce15f5ddb553af27097cf381fc3845560e85bed15642ea77d680' 
  AND token = 'cHxJNzDnIU0vZicccZh7osxWmkBbnCTw/JU0oewS0xA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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