SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffad48d3edbcad78b491a70b79d9c09abd95bc5d3df1feedf722e9dc68f59123' 
  AND token = 'TdInXrvPYXzM/ALui/hdJdiv88wQ9Xd/eE3Nua+d2Zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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