SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fc88a148022c2f7e35945c00aa54bad3679e4a2373693122dbe4c3cda7791c1' 
  AND token = 'MJ/HoSaVLxP59mVjDBFmIAmp65PgPmEWV3d8InlSbtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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