SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e2cee2d27f666927e453aa4a8e675a3cd43188ee451c7d6f78678e34607110d' 
  AND token = 'mMxR0MAWAmXE/RVtExcvwU5z8dol64oH1kSj60sRm8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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