SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4cb7b87d4e45f0fa6ea8fec31b2d83eb4579c7ea3550644b3f6b17aac1b7963' 
  AND token = 'SbOoT+tCjwfrhKdl/8cZakh7qB6XKVGhWzwkCtjB2Oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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