SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0e1fa1e3871add9f6f129cb795903bf3e239521149daaaad904ef78921913cb' 
  AND token = 'jOCy2Tcbyfe53VLG99HLChWIgJSkI0MauwP6zK0Rnd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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