SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '752bd901cc577fc4f000c0fa09c557808ea3e5d58a7c49596b08b34a56939925' 
  AND token = '5YV3XcYeSvithhMCCf+o2+YNTLFKHh0ODL/ocQrwuLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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