SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c253d48325d5e96a06823ba9987ea00fb290864d24d8ff7f9ec5f28429139860' 
  AND token = 'xylTuCZGCJOEmCZbukILHMsR1zjnvaZVfcx7wZQClps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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