SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e052d5da43613518f1af82c316830b16672d5d7b6cf79150816fc4b4c9fe75c3' 
  AND token = 'SER5xDvb7uacMeXWCExIS0C7CxI7oJWO3Y5dmjbaa84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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