SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48785d7a3fadf027fcc526af213109a56e9a13947ae1d8fed813a2dcedf837e1' 
  AND token = 'oUUmH3a3euewOyyYNjlOuGQvxIwve87J7+pTyTSMBYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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