SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7417d8822b25f00a2606c40f37318c8ffd49002578fc24e6836859be1f6ad010' 
  AND token = '1APxFFhwVrd4lEFS33WysET1SMuQVIP8mM4a/M18xJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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