SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12613761208c3f12c761c797b0a49404b5477a8558cdc5a90e534212a5888eb9' 
  AND token = 'cpXFhXzb6kDZimuwOGQode4WmXr7wywrQhX1/awSzSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}