SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8fdfafc40b97e8ee3ead89e88a38dec56a717395cb5d748251f5776c149dfc4' 
  AND token = 'snZx75zg2XmKbm8YWXLtuJ2jzJoR3yAyYomElicrLuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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