SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '453fc7225e6536778ff31db86bf148dcaf5b9f118163ce3880274adadf4afab3' 
  AND token = '1+0bpAYSg9VOYNIQ/rV5FhqJxo0QU//4QvrRWGJ8Cng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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