SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26471173afb8ecb0040e67a18767bf1ce98fee6f2cee606f1a359a171954380f' 
  AND token = 'OXxcJZhnDrWrsAd2k1FSENRqyq6wxaH3QS4fVZQzftY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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