SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '247d658067d073b5ff63446d00a03ef47f813ca24360eb73d85df9517d84a1b1' 
  AND token = 'VCz1xbQPsDDbc5tazlApUe2uFUjSWJXMdgTRb1pVn44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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