SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26b1b3d14aca26826fd383fffb134f87ed2b68240719865a2d5b3c318c124b94' 
  AND token = 'V5fYdX10lb3Atjg8OtyWZ5pWPj7tTZA1j+BfPdUttlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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