SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ab94ded094aa27389115ce54f24dab962c3a080ffee74a0fc9b3eba3da1737b' 
  AND token = 'TwHCH7qUzZhuhs4Awm4t9cVzxKMjMrT04rBlAcLOcHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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