SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'beed49ab14d9e1bc0b70debc9034c6fcfd55f12bdeaf1427fafe0d9383087b4b' 
  AND token = 'KEMOXUoVOed9vYQp83smiHVVRaSSFC6HGIFcPgYWg5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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