SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3228f719e46aa097750f322e4883ce0b3f789a63e7af447bb841519966b2ff6' 
  AND token = 'vuQa42I8UulVTCJBkgOOI17wXQLd2nqvtm3XZ/bYziI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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