SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1605200fe8348af77bbed87ef01364852421a8d61fb1b4de590e6407a4678fed' 
  AND token = 'b+ZD8qtnxcrly3cZussZSSpDbXJ3Sw2FQWJHq6rRCsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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