SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89adbfdf61080d166d922b595c21ee30ba2db6932e8f2a01866358dc19f4bd52' 
  AND token = 'Fkmi8UNfzkPJLOSJtgYG6VwKPix14o212FvTn8Prk68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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