SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4d47b7797a93fe68c49d0ac26a1825e1d49cd4eedd14a1a90ff4fddaebaf703' 
  AND token = '1mbAdBMiVVA5usunbBvClgfctIzjvsYCOmCoRFz9eEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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