SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '712c853d7e0f2f055a152577bb5fbb605afa8218395170e6884f11a4e47064e1' 
  AND token = 'rDcTKAFcpngXy46WDqFOjhliZwHfQpBcv8afRWp8b3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}