SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ea93c6b8f82b4a9808edf6ff35001aff7596ca5bf4ae0374868ee8a61b2b693' 
  AND token = 'HiAvPJifKHer76XlnTr9dELdMpBrSEB1fFDqdWlLZbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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