SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83868b55955ce630fa81ec02b306a079914cc04ac51b9ac43963ad694f8055c1' 
  AND token = 'DgN6EomDKmLIa0N0uaYO/Hlvm0ocPdEd4C9Eyxqt69c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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