SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc076052d0be380ba2e78d70bc848066d4e65ef026190220daf47bb044376c53' 
  AND token = 'wOiLVuEEk1HdkMvljAJsg+Y875KD5MhUWCvxbLcc2SI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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