SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd275d1b0f5bd92d2d9115977cff243109c6589dbeecb9bfb12e2841e2b913ed7' 
  AND token = 'lkrVfYgl3ZBkNnz8npFdpNvRVF9m/z8KGWHYr+uk+jU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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