SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ebcb924425ce69662bfeb83d1cac1f111fed9c0235412991a139b958ea6111d' 
  AND token = 'oCSKD1ROERJjgbC2rFq3rBtq+x84HC4zLeK2ofvFtsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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