SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82d5c7e03048d1feedb9e046782b6506dfbaef38f5163797941118424a11a4a6' 
  AND token = 'jWHKgmFSBhPmN4GrBpXO5doI56htMegGpQLiwYH7agE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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