SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7075bad832bf544af50e78085d759a9ba03954a925829f30e810437dc922f89e' 
  AND token = 'VABCtUlZ5QcDG119bmvtAlAY+BFJwnWzihww+eh/BTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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