SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f826d13190f758bada4a6901086f9d71f1cbf4e442548185990052dc54ec36a' 
  AND token = 'zStFo6j3PfhdMPu6Pqg0LGxyYgaYSdmajlelZIA6J94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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