SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff303942a0b9722d17a946be2f037ea3f07d88cd5e19cb9fce81852d4071e978' 
  AND token = 'oOS3HZ7LJ9rDm/bGCygZ0qzBciWtfwyKLaPOKikEvzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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