SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '827e97f889e5fb035676a658f766b96225b59ca15c4ff42d496e60832ddd68f5' 
  AND token = 'UP19wGQlJHs/GhGBz6qLCccsZLeoynhistdVbEbnYeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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