SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82575a99feafd03435c6382dc24357b2523e65e6fed079b5f93cadde2cd27cfc' 
  AND token = 'CXWs1dksQZ+zwYxBwGhUz3iuLnmCMNMW3+spr/FGToQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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