SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '518cdd254cfac6dfcd9a6bf6ea063e254561dfc914cb7168282f9f71c1099369' 
  AND token = 'y8++2W2kohQO2OEKqZ2lgcif4WPO/jM5gORoDKPl6oU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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