SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcecfeffc03c7168893a4030d38481c3ec93013e73d79ff5f3f501f9953ec791' 
  AND token = 'oVOd59sTWR7KBP3OEpXXblen3f2C+aR222CL+Cz9P18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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