SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9b1f08e12c514167e39891dd13a1065e0e192368cdefb083195b393d5dfc733' 
  AND token = 'Mkq5TlNbTOlemUPh68ZDc1imXtR97SWpcnjQayymZTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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